1. The Field of the Invention
Broadly conceived, the present invention relates to the storage and controlled dispensing of a predetermined portion of the length of a flexible, elongated member, such as a wire, a tube, a cord, or the like. More particularly, the invention pertains to the controlled dispensing of sterile cord or tubing used to interconnect devices employed in medical procedures. In one medical application, the present invention has specific utility in a system for electrically interconnecting to a monitor the output signal of a pressure sensing transducer used in connection with an angioplasty syringe.
2. The Background of the Invention
Flexible elongated members, such as wires, tubes, cords, or the like, are frequently utilized to interconnect locations or equipment that are separated by a distance shorter than the length of the elongated member itself. Thus, a lengthy extension cord may be used between a wall socket and a string of Christmas tree lights, where only a short length of cord needs to be added to the wiring of the lights. Alternatively, an intravenous feed tube of substantial length that is provided with fluid-sealing couplings at each end may still be used to interconnect a fluid source to a patient or to medical equipment which is very close to the source of fluid. While the interconnection function may be adequately performed by the overly long elongated member under some circumstances, the unused length of the elongated member can prove to be a problem.
First, lengthy, unused sections of such an elongated interconnection member clutter the environment and frequently become entangled with each other, or trip passersby. Such accidents may in turn result in the detachment of the interconnection member from the equipment to which it has been coupled, or the overturning and damaging of that equipment. Where a tube is involved as the elongated interconnection member, unused sections thereof have a tendency to become coiled upon themselves and then kinked, restricting or completely blocking fluid flow therethrough.
Unnecessary lengths of wires, tubes, or cords have been known to migrate out of the immediate vicinity of their utility to become trampled, pinched in doors, or otherwise abused. In some electrical applications it may be essential to keep an interconnecting wire from inadvertently moving into proximity with other electrical equipment or with ferror magnetic objects which may distort signals on the wire or be affected by signals passing therethrough.
Loose lengths of unused wires, tubes, or cords can stray out of properly designated areas and become contaminated by paint, chemicals, greases, or merely germs. In surgery an unnecessarily long interconnecting wire tube or cord can, by merely touching the floor or a non-sterilized piece of furniture, subsequently become the source of dangerous infection when medical personnel fail to recognize that it is no longer a sterile object. Handling such a contaminated length of wire, cord, or cord will then contaminate medical workers or even the patient, reducing the chances of preventing infection.
Thus a general need exists to contain and controllably dispense the portion of the length of an elongated member actually required for interconnection purposes, while at the same time retaining the unused length of the elongated member in a compact form which avoids tangling, snagging, damage, uncoupling, and contamination.
For example, one area in which the control of the unused lengths of an elongated interconnecting member has proved critical is in the environment of the modern surgical operating room. There, pieces of equipment, such as pumps, monitors, catheters, and sampling devices need to be interconnected variously with each other, with a patient, or with sources of electric power, positive or negative pressure, medication, or fluids in the form of liquids or gasses. These interconnections are accomplished using flexible elongated members, such as wires, cords and tubes, which convey fluids, communicate pressures or signals, and supply power. Unused lengths of these elongated interconnecting members can turn an operating room into a confusing jumble, capturing the attention of medical personnel in a web of distracting equipment, while presenting needlessly dangerous opportunities for tripping and/or equipment damage.
In many cases it is also essential to maintain the sterility of such elongated interconnecting members so that subsequently both intentional and inadvertent contact therewith by medical personnel or by other sterile equipment will not transfer contaminants thereto. Thus, particularly in the hopefully controlled environment of an operating room, the controlled dispensing of useful lengths of a portion of an elongated interconnecting member, and the retention of the balance thereof in a compact and sanitary form is desirable.
In the previous paragraph, one aspect of the present invention addresses this need.
Many interconnection systems for use in medical procedures can benefit from the incorporation of this aspect of the present invention thereinto. To give a concrete example, consider the field of angioplasty. Over time, blood vessels may become partially or totally blocked due to a buildup of cholesterol plaque along the walls of the vessel. One location where plaque buildup is particularly dangerous is within the coronary arteries which supply oxygen-rich blood to the heart. When plaque builds up within these arteries, a condition commonly referred to as coronary heart disease can cause serious chest pain, or angina, and may eventually cause heart failure. Angioplasty is a procedure for reducing the blockage which may occur in these and other blood vessels.
This is accomplished by inserting a balloon-tipped catheter into the blocked artery and inflating the balloon with a controlled syringe to compress the plaque at the blockage, thereby expanding the narrowed artery. Typically, an introducer sheath is inserted through an incision made in the groin or in an artery in the arm. An x-ray sensitive dye is injected into the coronary artery through a catheter that is introduced through the sheath. The dye enables the doctor through the use of real time x-ray techniques to clearly view the arteries on a television monitor and thereby to locate the artery blockage. A balloon-tipped catheter with a guidewire at the end thereof is advanced through the artery to the point of blockage with the help of the x-ray monitor. The catheter is placed in the middle of the blockage and inflated for approximately 10 to approximately 60 seconds. Thereafter, the balloon is deflated and the procedure repeated several times at different places to compress the plaque on the arterial walls. After the results are checked, the balloon catheter and guidewire are removed.
This procedure is much less expensive and less dramatic to the patient than the use of chemicals or open-chest by-pass surgery which has been common in the past. Accordingly, the number of angioplasty procedures of this type has increased dramatically each year. For example, according to some reports, as recently as 1987 some 200,000 patients suffering from coronary artery disease were treated using angioplasty procedures. Since coronary artery disease remains the No. 1 cause of death in the United States, it can be expected to continue to play an important role in the treatment of coronary artery disease.
While angioplasty procedures have the above-stated advantages, exact control of the pressure used to inflate the balloon-tipped catheter is nevertheless essential to the safety of the patient. The duration of such inflations is also of major importance. When the balloon catheter is completely inflated in order to begin compressing the plaque, blood flow to the heart is temporarily shut off. This creates the potential for initiating cardiac arrest.
Accordingly, the pressure exerted on the artery by the balloon catheter, as well as the duration of the blockage created by inflating the balloon catheter, must both be carefully controlled by the attending cardiologist and other operating room personnel. The previous use of syringe systems equipped with conventional pressure gauges and human observation of stopclocks and the like is gradually giving way to a more sophisticated and effective method for monitoring balloon inflation pressure in an angioplasty procedure. The syringe used to apply fluid pressure to the balloon catheter is in these more sophisticated procedures placed in fluid-communication with a pressure-sensing transducer, and the output signal from the transducer is communicated to a monitor which can display both timing and pressure magnitude data.
For convenience, the pressure sensing transducer is usually located at the inflation syringe itself, while the monitor used to display pressure and timing data is located at a convenient position in the operating room at a distance from the inflation syringe which may vary from one operation to the other. The inflation syringe is part of the sterile field maintained in the operating room, while the monitor itself is of necessity located in the nonsterile field in the surgery rooms. Under such circumstances, a clear need exists to electrically interconnect the output signal from the pressure sensing transducer and the inflation syringe to the monitor in a manner which permits surgical personnel to vary the distance therebetween. At the same time, however, excess unused lengths of the flexible electric cord used for such a purpose can become a problem for the reasons already stated above. Thus, excessive lengths of such cord and of other wiring and tubing used in the operation can become a dangerous and distracting clutter. Such entanglements impede the efficient movement of interconnected equipment and become hazards susceptible to causing tripping or, due to snagging, causing inadvertent disconnection of the equipment involved. Major but subtle difficulties arise when stray lengths of such interconnecting members fall out of the sterile field of surgery and thus become themselves contaminated. For example, the interconnecting electrical cord used to communicate to transducer output signals to monitor can, if not carefully restrained, touch the floor or some other nonsterile piece of furniture. Thereafter, the cord will communicate contamination into the sterile field by contact with personnel or other loose cords and wires. At the same time, however, there is a desire to afford the personnel conducting angioplastic procedures maximum flexibility in the amount of separation between items of equipment being used. The pressure monitor may be desirable at a greater or lesser distance from the inflation syringe, and any manner of coping with loose, excessive interconnection wiring must accommodate for this fact.
It is not uncommon in an angioplasty procedure to need to disconnect the equipment being utilized from the monitor therefor and later to reconnect these two pieces of equipment. Typically, this will occur when it is determined that a given balloon catheter is of the wrong size for the task to be performed. Then, it is necessary to withdraw the catheter, disconnecting the inflation syringe and the electrical wiring therefor. The equipment is moved to a sterile staging table where a catheter of the proper size is connected to the syringe. The new catheter, the syringe, and the interconnecting electrical wiring are then returned to the surgical table. The catheter is reinserted, and the electrical interconnection to the monitor is reestablished.
Nevertheless, in systems for interconnecting an angioplasty syringe to an electrical monitor, the acts of effecting coupling between the wiring, which is in the sterile field, and the monitor, which is in the nonsterile field, presents a challenge for the preservation of integrity of the sterile field. The individual who actually effects interconnection between the sterile cord and the nonsterile monitor is in the sterile field. Accordingly, it is necessary that the interconnection process be effectable without requiring that individual to contact the monitor. Adjustments of the monitor are, by contrast, usually made at the direction of surgical personnel by technicians who are not themselves in the sterile field. Nevertheless, where the sterile and nonsterile fields in the form of the sterile cord and the nonsterile monitor, respectively, are actually first interconnected, care is essential. The procedure can only be conducted by persons in the sterile field and then only if their contact with the nonsterile field is precluded.
Additionally, a system of interconnection for this purpose must include provisions for thereafter disconnecting the electrical coupling, and doing so entirely within the sterile field.
Thus, the control of excessive lengths of unused interconnection cabling, the preservation of the sterile field, and the provision of flexibility for affording electrical disconnection during surgery are concerns that call for equipment improvement and innovation.